Plants

Characteristics of plants

Classification of plants

Two main groups of seedless

plants

• Seedless nonvascular plants

– Do not have true roots stems and leaves

– Do have root like, stem like, and leaf like

structures

– Root like structures called rhizoids

– They include mosses and liverworts

– Spend most of their life in the

gametophyte stage

• Seedless vascular plants

Bryophytes - Mosses & Liverworts

• Liverwort – wort means herb

– Have flat thin photosynthetic liver-shaped

structures that are much like leaves

• Moss

– Slightly more complex than liveworts

Plant Life Cycles

• Alternation of generation

– Sporophyte stage (diploid)

– Gametophyte stage (haploid)

• Can also reproduce asexually by a

process called vegetative propagation

Importance of Mosses &

Liverworts • Pioneer species

(species that are first

to get established on

barren areas

• Begin the weathering

of rocks to make soil

Seedless Trachophytes • (Vascular plants)

• (plants that have

conductive tissue)

• Includes club mosses,

spike mosses, horsetails,

and ferns

• True roots stems and

leaves

• Vascular tissue allows

water and minerals to

move up and down

through out the plant

Seedless Tracheophytes

• Club mosses and

spike mosses

• Simple tracheophytes

that resemble true

mosses

• Reproduce spores in

cone-like structures

called strobili

Seedless Tracheophytes

• Horsetails

– Only one genus alive

today

– Slender stem and

small wedge shaped

leaves

Ferns • Range in size from small to

large as trees 15m

• Grow in moist areas

• Moisture is necessary for part of their reproductive life cycle

• Leaves are branched and have a lacy appearance

• Leaves are sometimes called fronds

• Ferns underground stems are called rhizomes

• Ferns grow as a tightly coiled fiddle head

The Fern life cycle • Fern leaf is called a frond

• On the underside of the leaf spores are produced by sori

• Gametophyte stage

– Haploid spores produced in sori

– Sori fling spores away from plant

– Spores that land on moist area grow into a heart shaped plant called the prothallus

– Prothallus produces egg and sperm

– The sperm swims to the egg

• Sporophyte stage

– After fertilization the zygote develops into a mature fern plant

Quiz

1. What are three characteristics of plants?

2. Give three characteristics of plants that allow them

to live out of water.

3. Plants are divided into two divisions. What are the

two divisions of plants?

4. Give two examples of nonvascular plants.

5. Give two examples of seedless vascular plants.

6. What is the difference between a gametophyte

plant and a sporophyte plant?

7. What is alternation of generation?

Seed plants

(Vascular Plants)

Gymnosperms

Angiosperms

• 250,000 species

• These are flowering plants

• The ovary encloses the seed

• The flower is the plant’s

reproductive structure

• Angiosperms’ success is

largely due to their many

ways of pollination

• Angiosperms are divided

into two groups.

– Monocots & Dicots

Monocots • Have one food storing leaf (cotyledon)

and is observed when it germinates

• Short for monocotyledon

• Leaves of monocots show parallel veins

• In monocots the vascular bundles are scattered throughout the stem

• Common monocots are, bananas, corn, barley, wheat, rice, orchids, tulips, iris and lilies

• Flowers of monocots are in threes or multiples of three

Dicots • Have two food storing leaves

that are evident when they emerge from the ground

• Short for dicotyledon

• Leaves of dicots show netted venation

• In dicots vascular bundles are in rings

• Common dicots are most of your fruits, legumes, forbs & trees

• Flowers of dicots are in fours or fives or multiples of fours or fives

Angiosperm Organs

• Roots

• Stems

• Leaves

Roots

• Anchorage, storage, & water

and mineral absorption

• Types of roots

– Fibrous

– Tap

– Adventitious

Stems • Stems are the link between the roots and the leaves

• Stems are either herbaceous or woody

• Herbaceous stems are soft green with little or no woody tissue

• Herbaceous plants come up annually

• Herbaceous plants support the upper of plant by fluid pressure in the stem called turgidity

• Loss of turgidity causes herbaceous plants to wilt

• Woody stems are stems supported by tough, dead xylem cells

Stems have two main types of vascular tissue – Xylem is the inner vascular cambium that takes minerals

and water up the tree

– Phloem is the outer vascular cambium that takes food and minerals down the tree

• Two main types of vascular

tissue

– Xylem is the inner vascular

cambium that takes minerals and

water up the tree

– Phloem is the outer vascular

cambium that takes food and

minerals down the tree

Stems

Woody Stem

Leaves

• Functions of the leaf is an increased area for photosynthesis

• Parts of a leaf

– Petiole

– Blade

– Midrib

– Vein

Types of leaves

• Simple

• Pinnate

• Palmate

• Compound leaf

• Palmately compound

• Pinnately compound

Leaf types

Flower Parts

Monocot or Dicot?

Quiz 1. What are the two divisions of seed plants?

2. Give two examples of gymnosperms.

3. What two groups are angiosperms divided

into and what is a distinguishing

characteristic of each?

4. What are the three main organs of an

angiosperm?

5. Draw a simple pinnate leaf.

6. Draw a simple palmate leaf.

7. Draw a palmate compound leaf.

8. Draw a pinnate compound leaf.